How can sin exist if their is no free will and everything is predestined?

In many of the world’s scriptures there is a mention that some things in life are pre-determined, but what this really means is largely misunderstood. the following verse are taken out of context. Here are the quotes missionaries use;
Sri Guru Granth Sahib Ji says,

“By one’s own actions, nothing can be done; destiny was pre-determined from the very beginning. By great good fortune, I meet my God, and then all pain of separation departs” (Guru Arjan Dev Ji, p.135).

Another quote from Sri Guru Granth Sahib Ji says,
“All things happen according to the Will of the Lord God. No one can erase the pre-ordained Writ of Destiny. He Himself is the True Guru; He Himself is the Lord. He Himself unites in His Union” (Guru Ram Das Ji, p.41)

and also,

“Union with Him, and separation from Him, come by His Will. We come to receive what is written in our destiny” (Guru Nanak Dev Ji, p.6).

On the surface, the terms ‘pre-determined’ and ‘fortune’ appear to suggest that a human being has no freewill and everything is being determined by God and the universe. However, these quotations have been taken out of the context of the entire Shabad (sacred hymn). You cannot take one paragraph and ignore what was before and after it. Read the following links;
http://www.sikhiwiki.org/index.php/SGGS_page_135
“In deep humility, I fall at the Feet of the Perfect True Guru (God)” (Guru Ram Das Ji, p.41). this means you are going towards guru with humbleness and lack of false pride “>http://www.srigranth.org/servlet/gurbani.gurbani?Action=Page&Param=41&g=1&h=1&r=1&t=1&p=0&k=0&fb=0

In context, it can be seen that the Word of the Guru (Gurbani) does not deny the fact that good deeds must be done through free will in order to get to get God-consciousness, which releases us from the system of reincarnation. Also, these hymns show that in the state of deep humility we realise that in the greater scheme of things, everything is in the hands of God, because the reality is that there is only one source of light, which permeates and radiates in different colours, much like a prism. This does not mean to say that there is no free will, just that we are all at the hands of the Divine Laws of the universe that the Creator set up and which can be found in nature. This includes the Law of Karma, which is the law of action and consequence or what you sow you shall reap.
Karmic Law of Action and Consequence

The system of Karma, gives us a greater insight into the workings of freewill and fate, and therefore give us an understanding of pre-determination and fortune. Sri Guru Granth Sahib Ji says, “According to one’s desires, one’s condition is determined” (Guru Nanak Dev Ji, p.1342), and “That alone is a good deed, O Nanak, which is done by one’s own free will” (Guru Angad Dev Ji, p.787). This hymn shows that pre-determination of a person’s destiny comes from what the desires of the mind are, which may be good or bad. The hymn also shows us that good deeds can only be free, otherwise they could not be called good. A further clarification of this comes from Guru Nanak Dev Ji, the first Sikh Master who says, “According to their own actions, some are drawn closer, and some are driven farther away.” Therefore, whether someone is destined to attain God-consciousness is a question of them desiring God instead of worldly attachment, and sowing the seeds of good actions, which has consequences of reaping good fruits.
Pre-ordained Writ of Destiny
A question sometimes arises of what the ‘pre-ordained Writ of Destiny’ is? Guru Arjan Dev Ji, the fifth Sikh Master, explains this by saying, “They spy on other men’s women, concealed in their hiding places. They break into well-protected places, and revel in sweet wine. But they shall come to regret their actions – they create their own karma.” The Guru therefore is telling us that we create our own destiny through our actions, and thus the pre-ordained writ of destiny is simply that which we have created for ourselves through our past actions from previous lives and our current life’s actions. In other words, our destiny or fate is the result of the consequences of the actions we have committed. Guru Arjan Dev Ji, the fifth Sikh Master explains, “O Nanak, only your actions shall go with you; the consequences of your actions cannot be erased.
Great Good Fortune
Another question is of that surrounding what having ‘great good fortune’ really means? This is referring to the very rare chance that a person realises the Law of Karma, that every action has a consequence, and how rare is that person who puts this into practice by doing good deeds, living honestly and meditating on God to achieve the meaning of life, which is to realise the soul and experience universal consciousness. This is reinforced by Guru Arjan Dev Ji, the fifth Sikh Master who says, “Among millions, how rare is that Gurmukh (one who listens to the Guru’s Teachings) who attains the Name (vibration of universal consciousness).” ,br>
Summary

• Sikhi supports the soft determinist viewpoint, that most of our actions are free and the rest are determined


• Our actions are free but we are still subject to the Will of God which is the Divine Law found in nature, including Law of Karma, action and consequence


• Our own desires and past actions (Karma) pre-determines and pre-ordains our destiny By great good fortune we realise this chain of action and consequence (Karma)


• Through freewill we chose our true destiny as a human being, which is realising God within ourselves. We chose to love God and do good actions of meditation, sharing and honesty that give us God-consciousness